Why do you feel that way? I'm not like opposed to Wonder Woman and Mister Terrific, but it's not really an exciting combo. Zatana and Mister Terrific on the other hand have the chemistry of coming about things from totally different ways, though not necessarily conflicting. And seeing them try to figure each other out and kind of gain from each other's approach could be really exciting. Man, that could be such a good book.
Selina Kyle and Clark Kent. The good boy with the bad girl, I could see them running across each other while she's in town stealing, hitting it off and having a little summer fling.
I don't see Zatanna and Mr. Terrific working. That's oil and water. They are from opposite extremes. They could be on an adventure together but a serious relationship? You're gonna give a good writer a really bad headache.
Wonder Woman and Mr. Terrific would be fine, but I don't feel like its a relationship that would be embraced by their collective fanbases (Wonder Woman's being far larger). I think Mr. Terrific pulls his weight a little better then Trevor does compared to Wonder Woman. They are both unique and best at what they do, however, Diana is still Wonder Woman. She's a God or demi-god depending on your canon. That's kind of a smothering relationship for his character. I'm not talking about Michael having insecurities I'm talking about the fact that she's Wonder Woman.
I don't care if it's the smartest man in the world, if he's dating Wonder Woman he's Diana's boyfriend first and foremost. Even if it's Batman. You can make him the perfect Bruce Timm DCAU version. If he's dating Wonder Woman everything else is overshadowed. I don't care how great he is. Wonder Woman is that great. You better be more than an average guy. I'm not saying you've got to be Superman but you've got to be on her level if this is gonna be an equitable relationship.
The J-man
It's because they are so different that I think Z and Mr. Terrific would work. It has tremendous dramatic possibilities. Tons of arguments followed by make-up sex. Very different views about what reality is, and how problems should get solved. I think a good writer could do wonders with that.
I admit that I haven't read that much of Michael Holt, but I thought he was a flexible person. Why wouldn't he be open to understanding magic?
Same thing with Zatanna.
Just based on all the incarnations of the characters, I don't see it. They could have a working relationship, but they are true opposites. I'm talking beyond him being a man of science and her being a magician. Their normal day to days are so different. One of them would have to have a character tweak/personality tweak. Look at Mr. Terrific in the Adam Strange comic or the Terrifics. Look at Zatanna in her 2009 series. Look at her in the New 52 and Justice League Dark. They could certainly go on an adventure together, but a long-term relationship.
I don't even think Zatana works with Batman. If you look back at the Batman TAS episode she's only a stage magician without any powers
Plus hasn't DC been trying to pair Zatanna with Constantine?
The J-man
It think "believable" isn't the same as "logical." It's great that characters no longer have to be coded at this point, so we can have someone like Connor who isn't a horndog without people assuming he might be gay. Maybe he's an Ace, or just something more interesting and nuanced somewhere on the spectrum.
We've seen her thoughts and soliloquies. I can't reference specific issues because I read them as a kid, but she wasn't always portrayed as having an interest in women.
We know from their team up issue in Waid's Brave and the Bold that she finds him very attractive.